An image processing apparatus and method for calibrating a depth of a depth sensor. The image processing method may include obtaining a depth image of a target object captured by a depth sensor and a color image of the target object captured by a color camera; and calibrating a depth of the depth sensor by calibrating a geometrical relation between a projector and a depth camera, which are included in the depth sensor, based the obtained depth and color images and calculating a correct feature point on an image plane of the depth camera that corresponds to a feature point of an image plane of the projector.